Device for centering of timber blocks and the like

ABSTRACT

A device for centering timber blocks or the like when being fed into sawing machines, in which centering means, swingably disposed for working on opposite sides of the blocks, are so coupled that they move from a normal position outwards from each other or inwards towards each other an equal distance, coupling of the centering device being achieved by means of one or more chains, bands or the like which run in opposite directions over chain wheels or the like attached to the centering means, and a spring device which determines the normal position if coupled with at least one of the centering means. The spring device consists of a screw and a nut working in conjunction with it as well as a spring mounted on the screw between the nut and a stop, which screw is given more or less tension by turning of the nut. The screw is connected to an arm mounted on the centering means, through a nut, which is penetrated by the screw. The screw is to be turned in relation to the nut in order to set the starting position of the centering means.

United States Patent [1 1 Andersson et al.

1 1 Jan.7, 1975 DEVICE FOR CENTERING OF TIMBER BLOCKS AND THE LIKE [73]Assignee: Skogsagareforeningen Mellanskog u.p.a., Gavle, Sweden [22]Filed: Sept. 21, 1973 21 Appl. No.: 399,495

[30] Foreign Application Priority Data Sept. 25, 1972 Sweden 12361 [52]US. Cl. 144/246 F, 144/246 R, 144/249 B, 198/204 [51] Int. Cl B27b 31/00[58] Field of Search..... 198/204; 144/208 R, 208 E, 144/242 R, 242 C,246 R, 246 A, 246 F, 249 R, 249 B; 83/436 Primary Examiner-Andrew R.Juhasz Assistant Examiner W. D. Bray Attorney, Agent, or Firm-Cushman,Darby & Cushman [57] ABSTRACT A device for centering timber blocks orthe like when being fed into sawing machines, in which centering means,swingably disposed for working on opposite sides of the blocks, are socoupled that they move from a normal position outwards from each otheror inwards towards each other an equal distance, coupling of thecentering device being achieved by means of one or more chains, bands orthe like which run in opposite directions over chain wheels or the likeattached to the centering means, and a spring device which determinesthe normal position if coupled with at least one of the centering means.The spring device consists of a screw and a nut working in conjunctionwith it as well as a spring mounted on the screw between the nut and astop, which screw is given more or less tension by turning of the nut.The screw is connected to an arm mounted on the centering means, througha nut, which is penetrated by the screw. The screw is to be turned inrelation to the nut in order to set the starting position of thecentering means,

2 Claims, 4 Drawing Figures PATENIED 3,858,631

SHEET 10F 3 PATENTEDJAN 5 3,858,631

SHEET 2 OF 3 170 FIG. 3 17b DEVICE FOR CENTERING OF TIMBER BLOCKS ANDTHE LIKE The invention relates to a device for centering of timberblocks and the like during feeding-in to sawing machines in whichswingably arranged centering means, to work on opposite sides of theblock, are coupled so that from a starting position (normal position)they move outwards from each other or inwards towards each other anequal distance. The linking up of the centering means is achieved bymeans of one or more chains, bands or the like which run in oppositedirections over chain wheels or the like attached to the centeringmeans, and a spring device, which determines the normal position, isattached to at least one of the centering means.

The purpose of the invention is to achieve a simple and operationallydependable construction of a device of said type which also makes simpleadjustment of the normal position for the centering means possible.

The invention is mainly characterized in that the spring device consistsof a screw and a nut working in conjunction with it as well as a springdisposed on the screw between the nut and a stop, said spring beingtensioned more or less by turning the nut, and that the screw isconnected to an arm mounted on the centering means via a nut which ispenetrated by the screw, the starting position of the centering meansthus being adjusted by turning of the screw in relation to the nut.

In this way centering of the block is achieved in relation to a givenpoint on the sawing machine into which the centered block is to be fedfor sawing into boards or the like. A precision centering device is ofimpor' tance for the quality of the sawn lumber, and a centering deviceaccording to the invention has been shown to fulfill all therequirements since it holds the block so exactly centered in relation tothe sawing machine that the control lines of the sawing machine and theblock coincide along the whole length of the block. In other words theblock will be cut exactly along the pith line of the log or trunk if thecentering device is set for this purpose. It has been shown that thismeans an increase in the average length of the sawn product therebyimproving the volume yield at the same time as the amount of wood, whichnormally goes to a chipper, is reduced accordingly.

An example of the application of the invention is described withreference to the enclosed drawing. FIG. 1 shows a plane view of anautomatic aligning device and a frame with a block centering deviceaccording to an embodiment of the invention. The rest of the figuresshow the block centering device in larger scale, specifically, FIG. 2 ina horizontal projection and FIG. 3 in a vertical projection, partiallyin section. FIG. 4 shows on a still larger scale the spring devicepartially in axial section.

In the schematic plane view according to FIG. 1, l designates a trunk ora block which comes to the device after it has been trimmed on twoopposite sides in a cant gang saw. The block comes in on a longitudinalconveyor belt 2 and is first stopped by a stop 3 at an appropriate sideposition directly in front of an automatic aligning device 4 onto whosecarrying rollers 5 and feeder rollers 6 the block is moved laterally ona lateral transport device 7. The block 1 is shown on the one hand inthat position where it has been stopped by the stop 3, and on the otherhand in a position 1', where it is in a block centering device 8 and haspartially been fed through a frame 9. The direction of feed is indicatedby the arrows 10. ll designates the middle line of the sawing machinewith which the center line of the block is to be made to coincide by theoperation of the centering device 8.

The centering means consist essentially of a pair of cranks with crankarms 15a, 15b and vertical axles 16a, 16b and taps 17a, 17b parallel tothem which function as bearings for the rollers 18a, 18b designed toengage with the block which is fed in between them. The axels 16a, 16bare carried in the bearing bracket 12 by means of bearing sleeves 19a,19b and on their outer ends they bear chain wheels 20a, 20b wedgedsecurely on the same. In the embodiment shown in FIG. 3 on each axlethere are two chain wheels which are mutually connected by means ofa hubshell 21a, 21b but in principle it could be sufficient with one wheel oneach axle, espe cially if the chain can be bent laterally or is replacedby a flexible band. A chain 22 runs over both the wheels 20a, 20b and inthe same manner a chain 22 runs over both of the other chain wheels. Thechains 22, 22 have their ends fastened on the wheels. The chains run inopposite directions over the chain wheels so that they run on the upperside of the chain wheel 20a when they come from the underside of thechain wheel 20b. If the movement is transferred by means of a cableinstead of a chain, the cable can be endless. An adjustable cable orchain lock 23 allows for control of the tension. The parts of the chainor cable, which are between the wheels, cross each other as is shown inFIG. 2.

With one of the chain wheels or corresponding crank arm 20b or 15b, anarm 24 is securely united to which a spring device is attached. Saidspring device is designated by 25 in FIG. 2 and is shown in detail inFIG. 4.

The spring device consists of a scrrew 26 and a nut 27 working inconjunction with it as well as a spring mounted on the screw between thenut and a stop 28 and threaded on a tube 28 on the screw. Said springcan be given more or less tension by turning the nut 27.

The arm 24, which in the embodiment shown is forkshaped at the bottom oris doubled, carries between the tines of the fork a nut 31 which, bymeans of taps transverse to the screw, is journalled in the tines of thearms 24. The screw 26 goes through and works in conjunction with the nut31. The screw 26 can be rotated by means of a hand crank 32 or the likemounted at its end. The tube 28' surrounding the screw is displaceablyjournalled in the wall of the bearing bracket 12 by means of aball-and-socket joint 33, 34. There is a stop ring 35 for a damper onthe ball, e.g., in the form of a rubber bushing 36 which sits on asleeve 37 concentric with the screw and enclosing the same. The handcrank 32 is also attached to the sleeve 37.

The operation of the device proceeds as follows:

In the starting position the crank arms 15a, 15b of the centering meansare parallel and have been set in this position by adjustment by meansof the crank 32 and the screw 26. In doing this setting the tension inthe spring is not changed since the stop 28 for the spring 29 isrotatable against the ball 33 and the nut 27 is brought along when thescrew is turned. The centering device 8 is adjusted on the guides 14 sothat its middle lies right in front of the middle point of the sawingmachine 9. The rollers 18a and 18b are spaced so that the block 1 willbe in contact with both of the rollers when it is advanced between themby the feeder rollers 6.

If, for example, a bulge on the left side of the block in FIGS. 1-2presses the roller 18a outwards, e.g., to the position 18a indicatedwith the dash-and-dot lines in FIG. 2, the axle 16a will turn and bringwith it the chain wheel 20a. This movement is transferred by means ofthe chains 22, 22' to the chain wheel 20b which turns the axle 16b inthe opposite direction to the axle 16a, the arm b thereby swinging outthe roller 18b, just as much as the roller 18a was previously swung out,to the position 18b indicated with dashand-dot lines in FIG. 2. Theblock is then centered in relation to the bulge so that its center willlie on the middle line of the centering device. This swinging out isdone against the force of the spring since the arm 24 presses the screw26 to the left in FIG. 2 so that the nut 27 presses the spring 29against the stop 28. Because of the spring force the rollers 18a, 18bwill always be held in contact with the block, if it has thosedimensions for which the centering device is adjusted. If the rollers18a, 18b swing quickly back from a swung-out position, so that the screw26 connected to the arm 24 is thrown to the right in FIG. 2, the shockis absorbed by the damper 36, 35.

If one of the rollers, 18a for example, due to an inward bend in theblock 1 is swung to the right in FIG. 2, e.g., to the position indicatedwith the dash-and-dot lines 18a, the roller 18b is swung via the chaintransmission inwards to the left in FIG. 2 just as much, i.e., to theposition designated with the dash-and-dot lines 18b, so that centeringis achieved in this case also. The spring 29, which is assumed to bepretensed the required amount by means of the nut 27, is then allowed toexpand by the nut 27 being drawn to the right in FIG. 4 by the screw,the tube 28 following with it and sliding on the ball 33. The stop 28stays in contact with the ball 33.

We claim:

1. In apparatus for centering timber blocks or the like being fed intosawing machines centering means ineluding assemblies swingably disposedfor working on opposite sides of a block, means coupling said assembliesso that they move from a normal position outwards from each other orinwards towards each other an equal distance, said coupling meansincluding at least one endless member running in opposite directionsover wheels or the like attached to said assemblies means, and a springdevice which determines the normal position coupled with at least one ofsaid assemblies and including a screw and a cooperating nut and a springmounted on the screw between the nut and a stop so that the screw may betensioned by turning of the nut, said screw being connected to an armmounted on said one assembly by a nut which is penetrated by said screw,said screw being turned in relation to the nut in order to set thestarting position of the centering means.

2. Apparatus as in claim 1 wherein said spring device can be adjustednot only in respect to the tension of the spring but also for adjustingthe normal spacing of the centering means.

1. In apparatus for centering timber blocks or the like being fed intosawing machines centering means including assemblies swingably disposedfor working on opposite sides of a block, means coupling said assembliesso that they move from a normal position outwards from each other orinwards towards each other an equal distance, said coupling meansincluding at least one endless member running in opposite directionsover wheels or the like attached to said assemblies means, and a springdevice which determines the normal position coupled with at least one ofsaid assemblies and including a screw and a cooperating nut and a springmounted on the screw between the nut and a stop so that the screw may betensioned by turning of the nut, said screw being connected to an armmounted on said one assembly by a nut which is penetrated by said screw,said screw being turned in relation to the nut in order to set thestarting position of the centering means.
 2. Apparatus as in claim 1wherein saId spring device can be adjusted not only in respect to thetension of the spring but also for adjusting the normal spacing of thecentering means.